Some conventionally known vehicle lighting units to be mounted in a vehicle body can control light distribution by using a light guiding member.
This type of vehicle lighting unit, for example, described in Japanese Patent Application Laid-Open No. 2012-022909 can be configured to include an LED (light emitting diode) light source disposed in a lower portion thereof and emitting light upward, and a light guiding lens (light guiding member) having a shape inclined forward and obliquely upward with inclined faces. Here, the light guiding lens is configured to receive light emitted upward from the LED light source along the inclined shape and then totally reflect the light by the inclined faces forward.
In the vehicle lighting unit described in Japanese Patent Application Laid-Open No. 2012-22909, the light is distributed forward only by the total reflection with the light guiding lens. Thus, the direction of light distribution may be limited due to the relationship with the critical angle of the light incident on the total reflection surface or the inclined faces of the light guiding lens. For example, the vehicle lighting unit with this configuration cannot distribute light to a direction obliquely downward and forward.
As a result, if light is to be distributed in a wider area, it is necessary to dispose an additional light source disposed at a different position to cause the light to be incident on the light guiding lens from a different direction, resulting in increase of parts number.